The increased demand for high-speed, high data rate communications has created an immediate need for broadband access to the related network infrastructure. New applications include computer-to-computer communications, gaming, and video-based services. Wireless solutions offer benefits in ease of deployment without the requirement of destroying streets to lay fiber. Wireless solutions also offer increased flexibility because new communication links can be added to the network as customers are added. Wireless solutions are also less expensive compared to optical fiber and hardwired solutions.
The use of millimeter wave (MMW) frequency bands allows wireless links to produce up to about an estimated one thousand times the data capacity of digital subscriber loop (DSL) or cable modem, systems, and offer a higher bandwidth than available at lower operating frequencies. Currently, many terrestrial wireless systems are built using point-to-point, point-to-multipoint, Local Multipoint Distribution Services (LMDS) and mesh architectures. Each link end contains an indoor unit (IDU) and an outdoor unit (ODU). The indoor unit usually has a modem and a power supply. The outdoor unit, which represents about 60% of the cost of the link, typically contains a number of subassemblies, such as a millimeter wave transmitter and receiver or an integrated transceiver, a frequency source, such as a frequency synthesizer circuit, a power supply, a controller, and monitoring circuits.
Different vendors usually manufacture these subassemblies. An outdoor unit is manufactured by mounting the subassemblies inside a large housing and connecting the subassemblies with cables and wire harnesses. The outdoor unit is tested and its operational character based on temperature changes is performed, which often takes hours to complete.
This method of fabricating and testing outdoor units is expensive, requires much manual labor, and results in low operational reliability.
FIG. 1 illustrates a typical prior art wireless, outdoor unit 30 used in terrestrial communication. As illustrated, this prior art outdoor unit 30 has a number of subassemblies that are functionally separate from each other and require individual testing and careful selection and manufacture to form the wireless terrestrial outdoor unit 30. A housing enclosure 31 supports a circuit or other mounting board 32 on which are mounted a millimeter wave (MMW) transmitter 33, a millimeter wave (MMW) receiver 34, and a large frequency synthesizer 35. An intermediate frequency (IF) processor circuit can be separate or part of other circuits and is operative for controlling operation of the frequency synthesizer, transmitter, and receiver. A power supply 36 provides the necessary power to the transmitter, receiver, and synthesizer. A waveguide filter 37 provides proper signal filtering for operation.
In this type of prior art outdoor unit 30, the various subassemblies are connected using expensive wiring harnesses and coaxial cables 38, as illustrated. Also, as noted before, different commercial vendors manufacture different subassemblies. The radio manufacturer buys these subassemblies from the different vendors, tests individual subassemblies before assembly, assembles the subassemblies into an outdoor unit, and tests the outdoor unit after assembly. The outdoor unit 30 is tested and characterized over temperature usually in large environmental chambers. This type of outdoor unit usually weighs over 20 pounds, and often costs between about $5,000 and about $10,000 in present day economic terms, depending on the desired performance and end use.